The proposed Phase I research project will be a series of proof-of-principle experiments designed to show the feasibility of using infrared fluorescence to detect blood flow in the submucosa of the human gut. This will be accomplished by retrofitting a sigmoidoscope for imaging in the near IR. The sensitivity of this system to detect fluorescence from the dye indocyanine green induced by irradiation with a near IR laser diode will be determined. The effective depth of tissue through which such a system can image will be determined. The completion of these studies will provide the necessary information to determine the efficacy of this type of imaging system. A positive result would suggest that this system could be more sensitive and more cost effective than the presently used fluorescein fluorescent flowmetry.